NO. 2127. 



OSTEOLOGY OF THESCEL0SAURZI8—GILM0RE. 



597 



ing posteriorly they gradually shorten. Chevrons are known to be 



present as far back as the twenty-sixth caudal, but is quite likely 



they persist, as in many other dinosaurs, nearly to the end of the tail. 



The first chevron is borne on the second caudal. The fourth chevron 



has a length of 97 mm., the seventh measures 88 mm., the tenth 77 



mm. 



Principal measurements of vertebrae. 



Scapula and coracoid. — The scapula of TJiescelosaurus is short, with 

 a widely expanded upper extremity. The total length is about that 



Fig 9.— Left scapula of Thescelosaueus neglectus Gilmoee. Paratype. 

 No. 7758, U.S.N. M. J NAT. size. External view. 



of the humerus. The similar lengths of these two bones is a most 

 unusual proportion in dinosaurian anatomy, and so far as I am aware 

 only found in TJiescelosaurus and Hypsilophodon in the Orthopoda. 



At the time of publishing my preUminary description of TJiescelo- 

 saurus the proximal portion of the scapula was not represented in the 

 available material (fig. 9), but the more recent discovery among the 



» Estimated. 



